This invention relates to a magnetic disc apparatus using, as a recording medium, a magnetic disc adapted so that a magnetic layer is formed on a disc substrate formed by molding a synthetic resin, and a disc cartridge for loading a magnetic disc into this magnetic disc apparatus. More particularly, this invention relates to a magnetic disc apparatus adapted so that a magnetic disc on which processing information processed by information processing equipment such as computer, etc. are recorded and a magnetic disc on which program information that a computer executes are recorded in advance are selectively loaded, and a disc cartridge within which such a magnetic disc is accommodated.
Hitherto, as a recording device for recording processing information processed by a computer, or for recording program information that a computer executes, there are used disc apparatuses using, as recording media hard discs using metallic disc substrates of steel such as aluminum, etc. Such disc apparatuses are of a structure in which magnetic discs serving as recording media are integrally assembled within the apparatus body along with the magnetic head units. In addition, disc apparatuses of this kind are used in a state integrally assembled within the computer body.
In disc apparatuses adapted so that a magnetic disc is integrally assembled within the apparatus body in this way, since it is impossible to exchange the magnetic disc, when there is necessity of recording new program information onto this magnetic disc, a magnetic disc unit for reproducing the magnetic disc on which such new program information are recorded is required. Magnetic discs such as a floppy disc can be exchangeably loaded with respect to such a magnetic disc unit. Namely, it is necessary to carry out an installation operation which is an operation to read out new program information recorded on the magnetic disc by one magnetic disk unit in which the magnetic disc can be exchangeably loaded to write the new program information thus read out onto the magnetic disc integrally assembled within the other magnetic disc unit. Further, since a magnetic disc such as a floppy disc has a small memory capacity, a large number of magnetic discs are required for recording program information of a large quantity. As a result, not only lengthy operation is required for the installation work, but also the work becomes complicated.
Moreover, in the case of recording processing information processed by a computer with respect to a disc unit adapted so that a magnetic disc is integrally assembled within the unit body, when the memory capacity of the magnetic disc becomes small, it is necessary to erase data recorded on the magnetic disc to ensure memory capacity. In the case of storing data erased from this magnetic disc, it is necessary to prepare another recording unit capable of exchanging a recording medium such as a magnetic disc or magnetic tape, etc. to record data with respect to this recording unit.
In the case where the magnetic disc unit in which the magnetic disc is integrally assembled is used as a recording unit for a computer as stated above, it is necessary to further use another recording unit. As a result, not only can the computer become large-sized, but also the installation operation of new program information and/or recording operation of processing information processed by the computer becomes complicated.
Further, as recording media on which information processed by a computer is recorded or program information that computer executes is recorded, there are used CD-ROMs which are reproduction only type optical discs.
In CD-ROMs, pit trains formed as very small uneven trains on a disc substrate (obtained by molding synthetic resin), are used to record processing information processed by a computer and/or program information that the computer executes. In the case of such CD-ROMs, a stamper, in which pit trains corresponding to the pit trains formed in the disc substrate are formed, is prepared. The stamper is loaded with respect to the metal mold of the molding unit to mold synthetic resin, thereby making it possible to manufacture a large number of the same CD-ROMs.
Since CD-ROMs can carry out high density recording, it is possible to record a large quantity of processing information or a large capacity of program information on a single CD-ROM.
Respective information recorded on the CD-ROM are read out by using an optical disc player provided with an optical pick-up unit. The optical disc player serves to scan the signal recording surface of a CD-ROM, rotationally operated after having undergone loading with respect to the disc rotational operating mechanism, with light beams emitted from a light source of an optical pick-up unit to detect return light beams modulated and reflected by pit trains of the CD-ROM with a light detector provided within the optical pick-up unit to thereby read out respective information.
Meanwhile, since the optical disc player serves to scan, while focusing light beams emitted from the optical pick-up unit onto recording tracks consisting of pit trains formed at the signal recording surface of the CD-ROM, recording tracks with these light beams to carry out read-out operation of information recorded on the CD-ROM, it is difficult to quickly provide access to a recording track at or in which desired information is recorded. Thus, a high speed read-out operation of information cannot be carried out. Moreover, since the optical pick-up unit includes therewithin a light source and a light detector along with an objective lens for focusing light beams on the signal recording surface and an objective lens drive unit for allowing the objective lens to undergo drive displacement, not only is the weight so large that this unit becomes large-sized, but also it becomes difficult to carry out high speed movement of the optical pick-up unit. As a result, it would become difficult to quickly provide access to a recording track at or in which desired information is recorded.
For this reason, in the case where information recorded on the CD-ROM is used in a computer, it is necessary for carrying out a quick read-out operation of information to carry out smooth execution of programs to record such information onto a hard disc adapted so that a quick read-out operation of information can be carried out.
Also, in the case where a CD-ROM capable of carrying out high density recording and having a large recording capacity is used as stated above, it is necessary to carry out recording of information onto the hard disc. As a result, it not only becomes difficult to improve operating ability of the computer, but also it is necessary to use a magnetic disc unit along with the optical disc player, thus making the computer large-sized.
An object of this invention is to provide a magnetic disc apparatus which can improve the operating ability of a computer provided with a recording unit and to realize miniaturization of the computer.
Another object of this invention is to provide a magnetic disc apparatus which can easily carry out supplementation or exchange of a program executed by the computer.
A further object of this invention is to provide a magnetic disc apparatus which can facilitate recording of processing information processed by a computer and storage of the processing information.
A still further object of this invention is to provide a magnetic disc with increased memory capacity and on which can be easily mass-produced.
A still more further object of this invention is to provide a magnetic disc which can be loaded on a magnetic disc apparatus with high positioning accuracy.
A further different object of this invention is to provide a disc cartridge which can accommodate a magnetic disc whose memory capacity has been increased and which can be selectively loaded with respect to the magnetic disc apparatus.
A still further different object of this invention is to provide a disc cartridge which can easily identify the kind of disc cartridge to be loaded and a magnetic disc apparatus adapted so that such a disc cartridge is loaded.
In an embodiment, the invention provides a magnetic disc apparatus using a magnetic disc adapted so that recording and/or reproduction are carried out by a magnetic head unit which experiences a floating force by air flow produced as the result of the fact that the magnetic disc is rotated. This magnetic disc apparatus is adapted so that there are selectively loaded: (1) first disc cartridge within which there is accommodated a first magnetic disc on which flat recording tracks are provided in a disc substrate formed by molding synthetic resin, and a magnetic layer is provided in a manner to cover the recording tracks, and (2) a second disc cartridge within which there is accommodated a second magnetic disc on which uneven information pit trains are formed in a disc substrate formed by molding synthetic resin, and a magnetic layer is formed in a manner including bottom surfaces and upper surfaces of the information uneven pit trains, the magnetic layer being magnetized in a state where the magnetization directions of the magnetic layer portion of the bottom surface of the information pit train and that of the magnetic layer portion of the upper surface of the information pit train are different from each other so that information such as programs, etc. for controlling computer are recorded.
In an embodiment the second disc cartridge within which there is accommodated the second magnetic disc on which information such as a program, etc. for controlling computer are recorded is loaded, thereby making it possible to install a new program with respect to the computer.
In an embodiment of the magnetic disc apparatus according to this invention further comprises a base adapted so that at least a disc rotational operation mechanism and a magnetic head unit are attached and a cartridge loading portion is provided, and a casing within which the base is accommodated, wherein an insertion/withdrawal hole of the disc cartridge is provided in the casing, and the disc cartridge inserted into the casing through the insertion/withdrawal hole is loaded with respect to the cartridge loading portion.
In an embodiment, this magnetic disc apparatus further comprises, within the casing, a cover opening/closing mechanism for allowing a cover body which opens/closes an opening portion provided in the disc cartridge thereby to undergo opening operation. In addition, in the magnetic disc unit, there is further provided a cartridge discrimination mechanism for discriminating different kinds of disc cartridges loaded with respect to the cartridge loading portion.
In an embodiment, as the second magnetic disc used in the magnetic disc apparatus according to this invention, there is used a disc including a disc substrate adapted so that xe2x80x9cinformationxe2x80x9d uneven pit trains in which data are recorded and xe2x80x9ccontrolxe2x80x9d uneven pit trains where control signals for controlling positioning of the magnetic head unit are recorded, are formed on one surface and flat recording tracks are provided on the other surface, a magnetic layer formed in a manner including bottom surfaces and upper surfaces of the xe2x80x9cinformationxe2x80x9d uneven pit trains and the xe2x80x9ccontrolxe2x80x9d uneven pit trains formed on one surface of the disc substrate, and a magnetic layer formed in a manner to cover recording tracks formed on the other surface of the disc substrate, wherein magnetization is implemented to the magnetic layer formed on the one surface of the disc substrate in a state where the magnetization directions of the magnetic layer portions of the bottom surfaces and that of the magnetic layer portions of the upper surfaces of the information pit trains are different from each other so that data are recorded, and magnetization is implemented to that magnetic layer in a state where the magnetization directions of the magnetic layer portions of the bottom surfaces and that of the magnetic layer portions of the upper surfaces of the control uneven pit trains are different from each other so that control signals are recorded.
Further, in an embodiment, at the magnetic disc used in this invention, there is provided a hub mechanism including a pair of holding members attached to the disc substrate in a manner to hold or put there between the peripheral edge of a center hole provided at the central portion of the disc substrate and a clamping member of metal attached to these holding members and clamped with respect to the disc rotational operation mechanism, wherein the pair of holding members of this hub mechanism are formed by synthetic resin having substantially the same coefficient of thermal expansion as that of the disc substrate.
In an embodiment, a disc cartridge loaded with respect to the magnetic disc apparatus according to this invention comprises a cartridge body within which there is rotatably accommodated either one of (1) a first magnetic disc adapted so that flat recording tracks are provided on at least one surface of a disc substrate formed by molding synthetic resin and a magnetic layer is provided in a manner to cover the recording tracks, the first magnetic disc being adapted so that recording and/or reproduction are carried out by a magnetic head unit comprising a magnetic head element provided on a slider caused to experience a floating force caused by air flow produced as the result of the fact that the magnetic disc is rotated, and (2) a second magnetic disc adapted so that there is provided a disc substrate formed by molding synthetic resin and adapted so that xe2x80x9cinformationxe2x80x9d uneven pit trains in which information are recorded and xe2x80x9ccontrolxe2x80x9d uneven pit trains in which control signals for controlling position of the magnetic head unit are recorded, are formed on at least one surface of the disc substrate, and a magnetic layer formed in a manner to include the bottom surfaces and upper surfaces of the xe2x80x9cinformationxe2x80x9d uneven pit trains and the xe2x80x9ccontrolxe2x80x9d uneven pit trains, the magnetic layer being magnetized such that the magnetization directions of the magnetic layer portions of the bottom surfaces and that of the magnetic layer portions of upper surfaces of the information pit trains are different from each other so that data are recorded, the magnetic layer further being magnetized such that the magnetization directions of the magnetic layer portions of the bottom surfaces and that of the magnetic layer portions of the upper surfaces of the control uneven pit trains are different from each other so that control signals are recorded, the second magnetic disc being adapted so that recording and/or reproduction are carried out by a magnetic head unit comprising a magnetic head element provided at a slider adapted to experience a floating force by air flow produced as the result of the fact that the magnetic disc is rotated; an opening portion for insertion of the magnetic head unit provided at one side surface of the cartridge body; a cover body for opening/closing this opening portion; and a central opening portion for allowing at least the central portion of the magnetic disc to face toward the exterior.
In an embodiment, the opening portion provided at the cartridge body is opened or closed by a cover body provided at the front of the insertion direction side into the magnetic disc apparatus of the cartridge body, and rotatably supported with respect to the cartridge body so that it can be rotated in a direction parallel to a plane surface of the cartridge body and biased by a biasing member in a direction to close the opening portion. At this cover body, there is an engagement portion engaged with a cover body opening member provided at the magnetic disc apparatus side when the disc cartridge is inserted into the magnetic disc apparatus.
Still further different objects of this invention and more practical merits obtained by this invention will become more apparent from the description of the embodiments which will be explained below.